Glera is a white variety of grape of Slovenian and Italian origin, possibly from the traditionally Slovenian-populated village of Prosecco on the Slovenia-Italy border, now in Italy.

[2] It has been proposed that it was cultivated already in Roman times,[3] possibly as the vinum pucinum praised by Pliny the Elder, although that is not known with any certainty.

When the higher DOCG status was sought for Prosecco di Conegliano e Valdobbiadene, it became a complication that the grape (which had become cultivated over a larger area, including outside Italy) and the protected designation of origin had the same name.

To resolve the issue, within the EU the old synonym Glera was officially adopted for the variety at the same time as the DOCG was approved in 2009.

[5][6] The change reduced the ability of other producers (in Italy and overseas) to label sparkling wines made elsewhere as "Prosecco" by using the grape variety's name.